Chittagong University of Engineering & Technology

About: Chittagong University of Engineering & Technology is a education organization based out in Chittagong, Bangladesh. It is known for research contribution in the topics: Computer science & Renewable energy. The organization has 1200 authors who have published 1444 publications receiving 10418 citations. The organization is also known as: Engineering College, Chittagong & Bangladesh Institute of Technology, Chittagong.

Design and Implementation of a Matrix Converter Using Direct IGBT Switching Method

Abstract: Prime outcomes of this paper are to convert fundamental frequency into two times and four times on both single-phase and three-phase systems. Instead of Sinusoidal Pulse Width Modulation (SPWM) method here we used direct IGBT switching technique with a matrix converter for improving the conversion. When we pay attention to the final output waveform, we found that it contains some harmonic distortion. To minimize this distortion, a conventional filter is incorporated with this simulation model, which was designed by PSIM software. The higher-order conversion of frequency given less distortion. The most efficient method of controlling the output voltage is to consolidate PWM control within the converter. The bottom line of this research is increasing the efficiency, and we have shown that the three-phase system exhibits higher efficiency than single phase.

DFT insights into new B-containing 212 MAX phases: Hf2AB2 (A = In, Sn)

Abstract: 212 MAX phase borides are new additions to the MAX phase family with enhanced thermo-mechanical properties. In this article, first-principles calculations have been carried out to explore the mechanical properties, Vickers hardness, elastic anisotropy, thermal properties, and optical properties of predicted thermodynamically stable MAX compounds Hf2AB2 (A = In, Sn). The structural properties are compared with the available data to assess the validity of calculations. The mechanical stability of Hf2AB2 (A = In, Sn) compounds is established with the help of the computed stiffness constants (Cij). The possible reason for enhanced mechanical properties and Vickers hardness of Hf2SnB2 is explained based on the analysis of bonding strength, followed by the electronic density of states. Higher mechanical strength and Vickers hardness of Hf2AB2 (A = In, Sn) compared to Hf2AC (A = In, Sn) are also indicated in the light of charge density mapping. The values of Pugh ratio, Poissons ratio and Cauchy pressure predict brittle character of the studied compounds. Besides, the anisotropic nature of the titled borides is investigated by 2D and 3D plots of elastic moduli along with some well established anisotropy indices. Thermal properties were investigated by calculating the Debye temperature, minimum thermal conductivity, Gruneisen parameter, and melting temperature. The thermal properties of Hf2AB2 (A = In, Sn) are also superior to Hf2AC (A = In, Sn). The optical constants such as real and imaginary parts of the dielectric function, refractive index, extinction coefficient, absorption coefficient, photoconductivity, reflectivity, and loss function are investigated.

Comparison Among ECG Filtering Methods for Non-linear Noise

Abstract: Electrical functioning of the heart can be translated into a waveform known as Electrocardiography. Perfect diagnosis of heart is very much difficult due to different kinds of noise such as biological signal (EMG), power line interference and Gaussian noise interact during extraction. Several research have been studied in last few decades to develop effective algorithm for eliminating the high frequency noise between any two beats of continuous ECG signal. However, existing metric is capable to eliminate the noise with sacrificing a portion of the ECG rhythm. This study proposes a novel Daubechies wavelet based noise elimination algorithm to remove noises (such as power line interference and random Gaussian noise) from ECG signal. The proposed algorithm presents the best functions of the mother wavelet for eliminating ECG signal noises without scarifying the ECG waveform pattern. Therefore, the propose system maintains the necessary diagnostic information without any distortion of the original ECG signal, maintaining a high SNR and low RMSE with respect to the Haar wavelet and low-pass filter.

Dual Orthogonal Feed Circular Polarization Array Antenna Using Microstrip Slot Feed Network

Abstract: This paper presents a new circularly polarized microstrip array antenna using dual-orthogonal feed technique. The feed network for 1x2 array is designed using microstrip lines and slot lines by applying double-sided MIC concept effectively. 90 degree phase difference between two orthogonally feed signals os created by choosing appropriate feed point in the feed network to advance one of the feed signals by quarter wavelength (lemda/4) from other. Excellent radiation performance is obtained from this proposed antenna with low cross polar component. The impedence (<-10dB) bandwidth of the array is 9.1% and the 3-dB axial ration bandwidth is 1.85% (9.905GHz to 10.09 GHz). The average gain is higher than 9dBiC over the 3-dB AR bandwidth. The relation between antenna dimensions and characteristics ia also investigated with a parametric analysis of the antenna.

An Efficient Technique for Detection and Enhancement of Blood Vessels from Cardiac MRI

Abstract: Cardiovascular diseases, mainly caused by stenosis or aneurysms of arteries, are the leading reasons of death worldwide. Angiography, which is not only invasive but also risky, painful and costly, is the common method for the recognition of such diseases. However presently non-invasive and radiation free cardiac MRI is being used to evaluate the function and anatomy of the heart chambers, heart valves and blood flow through major vessels. The morphology, formation and plaque buildup conditions of blood vessels indicates diseases such as heart attack, stroke, angina, arrhythmias, heart failure etc. Thus, the vessels needs to be identified properly and clearly. In this paper, cardiac MRI is used for accurate extraction and enhancement of blood vessel, emphasizing upon the minor and somewhat discontinuous vessels. MRI technique in this field was less explored and is very challenging because of poor contrast difference between the vessels and organs and mentionable amount of noise. The detection process uses both morphological operators and image gradient characteristics. The result obtained by using morphological operators has better effectiveness in terms of noise reduction and accuracy.